Urban Moths

This is a page on the moths of Mumbai. Even in this big city, moths can be
seen all year round. But the two months between the end of the rainy season
and the beginning of winter is when they swarm. I've been photographing the
few which wander indoors for about a decade. While trying to identify them,
I found that very little is actually known about them. So here is an attempt
to put together some simple observations, in the hope that they will be
useful. If you mail me new information, including corrections, possible,
partial, or complete IDs, I'll be happy to acknowledge you here.

[#25]
superfamily Pyraloidea,
f Crambidae/Pyralidae?
Because of the placement of the antennae and the shape of the snout.
Tempted to call this Parotis marginata, but it is
not, because it lacks the brown marginata in its wings.

[#76] superfamily Pyraloidea,
f Crambidae/Pyralidae?
Because of the placement of the antennae and the shape of the snout.
Not the same as [#44], but there seems to be some confusion in the
identification of the two. In various places moths which look like Stemorrhages costata are also called Palpita, for example,
P. unionalis, etc.

size: 2-4 cm

a few specimens seen

Recorded on 15 Oct, 2014

[#A1] Order Plecoptera?

size: 1-2 cm

a few seen

Recorded on 7-9 Oct, 2014

[#A2] Order Plecoptera?

size: 1-2 cm

a few seen

Recorded on 7-9 Oct, 2014

The easiest way to spot moths in a city is to keep a light on at night. Some
of the larger moths can only be seen at night. Many of these are drab in
colour. If they are seen during the day, then they may look like bird
droppings on a leaf, or a piece of dry leaf stuck on a branch. Such desperate
camouflage could mean that they make tasty morsels for birds. You can
occassionally see them in your house, hiding in the folds of a curtain, or
wedged into a dark corner. Then there are the moths, usually smaller,
which remain on your walls through the day. These are often interestingly
patterned. The fact that they do not bother to hide, and are not eaten up
by birds and lizards may mean that they are unpalatable and secrete toxins.

Is this just a neat story? The larger nocturnal moths which disappear during
the day are usually from the Noctuoidea superfamily. Many of these moths eat
plants which are full of toxins. Often insects which are seen to be unpalatable
to predators are known to feed on such toxic plants. So that could make many
of these cryptic moths toxic, and without need of camouflage. So the situation
may be more complex than it first seems.

Moths are of economic importance partly because of the damage they
can do to crops.

A Geometrid caterpillar exhibits its characteristic looping
movement as it gobbles the leaves off a methi plant.

The dark mess on the leaves of a methi plant could be the eggs of a
Geometrid moth.

In any case, find it interesting to count the number of each species I can identify. You
see only a few specimens of most species. The rest are abundant, and one can
do statistics with them. Generally the number of moths attracted to a light
seems to vary with the temperature and humidity: the hotter and more
uncomfortable you feel, the more moths you can see. In the first week of October
in 2014, most of the moths seemed to belong to superfamily Pyraloidea. In the
second week they seemed to be outnumbered by Noctuoidea.

FC is a frequency count. An external light is kept on all night, and clusters
of 10 moths are counted in the morning. FC for any species in a cluster is
the fractional count for that species in that cluster. Since the spread in
counts can be large, at least four clusters are counted to give a spread in
the FC. Since Noctuoidea disappear by morning, FC counts only the distribution
of Pyraloidea.